What they have done since is awe-inspiring, and should give hope to any football purist that even in today's money-driven game, success can be achieved organically.

Since Juergen Klopp's appointment as head coach in 2008, BVB have promoted young talent like Mario Goetze and Nuri Sahin and have brought in a wealth of top prospects, such as Mats Hummels and Robert Lewandowski, on the cheap. Despite massive interest from some of Europe's biggest clubs, they've largely been able to retain their best players, extending contracts in most cases.

Still, Dortmund have a very long way to go if they are to establish themselves permanently as international—and even domestic—powers. This season has exposed their inadequate depth as strain from the Champions League has seen the Bundesliga title holders drop too many unnecessary points and resulted in a premature end to their defense of the title. And their performances against the Spanish, English and Dutch champions will be for nothing if they exit the Champions League in the first knockout round.

The 2013 calendar year is a critical one in Dortmund's history. Read on for a breakdown of what the Ruhr side must do over the next 12 months if they are to affirm their potential.

Reach the Champions League Quarterfinals and Finish Well on the Domestic Front

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Dortmund have done great things this season, but are still a long way from any real success. As few as three draws (one in the DFB-Pokal and a subsequent penalty shootout defeat, two in the Champions League with a deficit of away goals or loss in penalties) could see their season turn into a total disaster. It's not enough to end the season as "also-rans" in three competitions.

Advancing in the Champions League ahead of Shakhtar Donetsk will be no easy task. While volatile, they are are extremely dangerous at their best, and no club can be comfortable visiting eastern Ukraine in February. BVB must nonetheless reach the last eight at the bare minimum if they are to affirm their status. From there, it all depends on the draw: Even a loss will be acceptable if it is a close contest against a team like Barcelona.

On the domestic front, Dortmund have the DFB-Pokal and Bundesliga to consider. BVB face Bayern in the next round of the Pokal, and the winner of that clash will be favorites by a mile to win the final in May.

Dortmund cannot be expected to win their clash with Bayern, but progress is a necessity if they are to stand a chance of retaining their status as Germany's strongest club.

As for the Bundesliga, second (or even third) place will do if Dortmund can win the Pokal and reach the last eight of the Champions League. The difference between spots two and three is trivial, and the Schwartzgelben will be decidedly more focused on tournament matches.

Even if it costs €5m or more per season, Dortmund absolutely must retain the 24-year-old. Strikers who can reliably score 30 or more goals per season are expensive, very hard to find and typically take time to settle in at a new club. BVB have to hit the ground running next season, and there is no better striker to help them do just that than Lewandowski.

And not only from a sporting perspective—it's also essential for the club's narrative for Lewandowski to extend. Dortmund are on the cusp of becoming a big European team, but have lost a key player in each of the last two seasons. It's not becoming of a big team to sell stars like Nuri Sahin and Shinji Kagawa, but if BVB can keep Lewandowski and seal new deals for Marcel Schmelzer and Neven Subotic, it will mark a huge milestone in their latent history.

Extend Contracts of Schmelzer and Subotic

Marcel Schmelzer and Neven Subotic are perhaps the lesser of Dortmund's defenders, but both are vital players in Juergen Klopp's team and will do anything for the club's success.

The former is perhaps a limited player, but his passion and energy are not to be underestimated. Schmelzer's winner against Real Madrid was arguably the biggest goal a Dortmund player scored since Lars Ricken put the result of the 1997 Champions League final beyond a shadow of a doubt.

Subotic, meanwhile, has formed an outstanding partnership with Mats Hummels, and the two can and likely will be Dortmund's starting center-backs for the majority of the next decade. Even though Subotic has his moments of madness, he plays very well on the regular, and replacing center-backs is never an easy task. Subotic and Hummels have a good understanding with one another and are reliable.

Build a Squad Capable of Competing on Three Fronts All Season Long

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The 2012-13 season has to date been a hugely important one in Dortmund's recent history.

BVB have proven their class against elite opponents outside Germany, but although their first XI may be elite, their inability to provide any challenge to Bayern in the Bundesliga has exposed a severe lack of depth.

Looking forward, Dortmund can no longer operate with only LukaszPiszczek and Marcel Schmelzer as viable fullbacks. Deputy left-back Chris Loewe played in the RegionalligaNord before his move to the Signal Iduna Park, and backup right-back Oliver Kirch operated as a holding midfielder at now-second division Kaiserslautern as recently as last May. Kevin Grosskreutz and JakubBlaszczykowski have recently tried their luck in the fullback positions, and neither has the positional awareness to take on a strong attacker.

Apart from the fullbacks, Dortmund desperately need more depth in defensive midfield. Sebastian Kehl will be 33 in February and is often injured. Sven Bender has only been fit to play in approximately half of Dortmund's games since the autumn of 2011, and due to the breakneck pace at which BVB play, the Ruhr side can only expect fatigue and injuries to pose problems for their hardest-running players. Sebastian Rode and NuriSahin would be excellent and potentially very affordable buys in the summer, and could provide rotation opportunities with Bender and IlkayGundogan, respectively.

The final position where Dortmund could do with some depth is at center-forward. If Robert Lewandowski leaves, BVB will need a classy replacement. Even if the Poland international stays, Julian Schieber is not exactly reliable cover. Dortmund may get plenty of goals from midfield, but without a top-class striker in their first XI, they will be found lacking in the fixtures that matter most.

Bring Back Nuri Sahin

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This is a special case of the previous slide, but deserves one of its own.

Born just 40km from the Signal Iduna Park in Luedenscheid and a BVB player for 11 years, Nuri Sahin is Dortmund's lost son. He tried to make the leap at Real Madrid and failed. And now, even with modest competition during his loan spell at Liverpool, it's been a month and a half since he last appeared in a Premier League match.

If Nuri can't play ahead of the likes of Jordan Henderson, he has no future at Liverpool—let alone Real Madrid or nearly any big club. Provided that his situation remains the same until season's end, Los Blancos will surely let him go, and the only realistic options are Turkey or the Bundesliga.

In separate interviews, Dortmund chiefs Hans-Joachim Watzke and Michael Zorc recently suggested BVB could sign the 24-year-old Nuri, who for the right price would be a great coup. While the Turkey international has been far from his best since leaving BVB, he is an undeniably top-class player who was regularly playing professional football even before his 17th birthday. Juergen Klopp once before moulded him into a superstar, and can surely do it again.

There is a real need in Dortmund for a player like Nuri. Because the club plays at breakneck pace, the central midfielders typically average more than 12.5km run per game. It may be humanly possible to sustain such a pace on a weekly basis, but during long stretches of games every three or four days, it's nearly impossible. Just ask Sven Bender, who rarely goes for a long stretch without being injured in some way.

With Sahin in the squad, Klopp can incorporate him and Ilkay Gundogan into a rotation such that BVB will always have an excellent ball-playing option in defensive midfield. Nuri will have to accept being a substitute at least at the start, but he will no longer have to suffer the humiliation of watching from the stands as many vastly inferior footballers play ahead of him.

Distribute Young Talents to Their Appropriate Level

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The recent confirmation of Marian Sarr's transfer from Leverkusen was just the latest in a growing history of talent aggregation at Dortmund. Many of BVB's current staff joined between the ages of 18 and 20, and now Juergen Klopp is grooming the next generation of stars. But he has to be careful and responsible when dealing with a long list of potential stars.

Also in the age group of the 17-year-old defender Sarr are striker Nick Weber and midfielder Jeremy Dudziak. In the 18-year-old bracket are striker Marvin Ducksch, defender Koray Gunter and newly-signed goalkeeper Hendrik Bonmann. There are 19-year-old midfielders in the form of Leonardo Bittencourt and Mustafa Amini, as well as 20-year-olds Moritz Leitner and Erik Durm. Marc Hornschuh and Lasse Sobiech are 21, and Julian Koch is 22: all three either are currently on loan or have been in the past.

Half of the above are unlikely to ever get much playing time with the Dortmund senior side, but many have real potential waiting to be tapped. Still, this talent will never be fully cultivated without opportunity, and Klopp cannot afford to gamble with too many raw and unproven talents. Leitner is an example of a player who could be a real star if he were given more opportunities. He's still too raw to be relied upon to hold the midfield in a big Champions League fixture, but perhaps after a year on loan at a 1. Bundesliga side he'll be able to play a bigger role.

Bittencourt and Gunter have huge potential, and both will likely be ready for a loan spell in the 2. Bundesliga next season. Ducksch perhaps as well, but much depends on how he plays this spring after a metatarsal fracture. None of the above appears ready to make a significant contribution to the Dortmund senior team, but all three may be too good for the BVB reserves next season—especially if they are relegated back to the Regionalliga West.

To date, Dortmund have a good record for responsibly managing talent. They've signed many promising prospects, and all have had their chances. But now, as their youngsters vie with many world-class stars for playing time, BVB must be careful not to waste the talent they've created and brought to the Ruhr area. It's for the good of the players, as well as the club's ethos and reputation.

In 12 Months' Time, Be Alive and Well in Three Competitions

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Half-way through the 2012-13 season, Dortmund are in good standing in the Champions League and DFB-Pokal, but are miles behind in the Bundesliga. It's a good standing given their current status and resources, but it is not becoming of an elite European club to be hopelessly out of the domestic title race in mid-season. They can do better.

Heading into next season, Dortmund should have a lot going for them. And at the very least, their opportunities are still in their own hands. Provided they meet all the aforementioned goals by September 1, they will have all the facilities to be in good standing in three competitions at this point next season.

Combined with success (especially in the Champions League), the extensions of Lewandowski, Schmelzer and Subotic will make Dortmund an attractive place for new stars. Performance will also beget money to sign these talents, and the level-appropriate loaning of their young talents will ensure that Dortmund have a new generation of core players ready to take their chances in the years to come.

Dortmund have come a long way, but are still not yet at the level of a consistent continental power. The 2013 calendar year is a critical one for them; if they can fulfill their potential, they will become a club to be feared by any other for years to come.